I think a smaller hide would be apporiate as they like to feel surounded on all sides try taking off the lamp and see what your temps are i gaurntee that it will help with the humidity also what i do to help my humidity is get wash clothes and wet them with warm water and put it on the top on my viv and it drasticly changes the humidty.
also get somthin to cover 3 sides of your viv this will help with him being secure i got black poster board and cut it to the exact deminsions it works really well and is very cheap.